Stereoscopic projection of motion pictures



May 20", 1924. 1,494,795

C. P. MULLER STEREOSCOPIC PROJECTION OF MOTION PICTURES Filed May 11, 1920 15 IR 5 IL 14 Arrbmvtr Patented May 2D, 1924.

UNITED STATES "494,195 PATENT OFFICE.

Cm I. I'U'LLER, OF BRONX, NEW YORK.

STEREOSCOBIC PROJECTIO N OF MOTION PICTURES.

Application meaxa 11.1920. Serial its/380,553.

tures on a strip or film as well as a novel method of producing such strip or film.

In the projection of ictures by means of an advancing strip or 1m it is well understood that the retina of the eye will retain for a sufiiciently long period impressions received from a number of pictures displayed consecutively so that, in accordance with the present invention, a pair of dissimilar but matched pictures taken from different view points may be successively projected to give a stereoscopic eflfect. I

In the accompanying drawings which illustrate diagrammatically the manner of producing a stereoscopic strip or film- Fig. 1 shows an arrangement of the pictures on the ne atives first obtained.

Figs. 2 to 4 il ustrate one method of effect-v ing? positive therefrom.

igs. 5, 6 and 7 illustrate a method of effecting coincidence of corresponding points in a particular focal plane.

Fig; 8 is a diagrammatic view illustrating the method of retaining the effective width of the film.

Similar characters of reference designate corresponding parts thruout the several I views. 1

Referring to the drawings, a film or strip of any standard or special type may be employed; and, in accordance with the invention, two such negative films 10 and 11 are exposed simultaneously to hotograph the same object or scene from difierent points. The said films are fed forward in wellknown manner by any suitable camera apparatus (not shown) to provide a series of pictures 1 L, 2 L, 3 L, etc., and 1 R, 2 R,

, 3 R, etc., respectively arranged longitudinally and successively on the said filnis1O and 11. It is essential, however, that the exposuremf two corresponding pictures 1 L and 1 R, as hereinafter more particularly forth,.shall be made simultaneously. I am aware that it has been proposed heretofore to expose a film from different points but alternately, more particularly in connection with color cinematography; also, to provide successive'pictures, one of each pair of which pictures consists of. two partial-views of the same subject taken from a different point.

However, such expedients do not produce the desired result; for, to secure proper stereoscopic effect, the two corresponding pictures taken from difierent points must not only be simultaneously produced but be matched as hereinafter set forth. In other words, the two matching pictures 1 L and 1 R are taken simultaneously from different view points and are arranged in corresponding pairs on a common single strip of positive film 12 or 13, Figs. 2 and 3 and in succession, that is to say longitudinally of the film-one picture of a palr being first projected and then the other. For example, the 1 arrangement may be as 1 L, 1 R,-2 L, 2 R, etc.; or, the picture taken from the right hand side may be arranged first on the film, whereupon the series will become 1 R, 1 L, 2 R, 2 L, etc. It is quite immaterial, also,

whether the right or the left hand picture be at the beginning.

In the printing of the positive to produce a film as shown in Figs. 2 or 3, various expedients may be resorted to. For example, as shown in Fig. 4, a strip of positive film 14 may be printed with alternate exposed and unexposed portions 15 and 16 respectively,

the film strip 14 then being first made from the negative film 10. Thereupon, the negative 11 is used and the exposures made in the unexposed spaces, it being understood, of course, is to be fed twice as fast as the negative. It is to be understood, also, that the particular manner set forth of producing a positive may be varied and that, as hereinbefore stated, the particular sequence of the pictures of a pair is not essential providin the numerical sequence set forth be maintained. Howev 11: is essential that the pictures .on the. positives'12 or 13 are ed ongitudi ii ally of said film in order to ring corresfiiinding points of each picture of a pair of pictures and substantiall for a given focal plane into exact coincidence. To effect this result, it is necessary to laterally displace each picture 1 L, 1 R, etc., toward the median line of the opcriv that in this procedure the positive impaired. However,

.tive film or positive, since the two pictures have been viewed from displaced or separated points. For example, a point X on the film negative 10, as shownin Fig. 5, which appears on the one side of the me dian line a-a may appear on the opposite side on the negative 11, Fig/6. Therefore, it becomes necessary in printing to laterally shift, or mask, each film so that when superposed in the projection, as indicated in Fig.

the projected image of the point X. from the two pictures 1 L and 1 R of a pair will coincide. It will be understood, of course, that this is strictly true only for a particular focal plane, or plane in proximity thereto, but as the projection of mot-ion pictures is usually of subjects taken in substantially one particular plane, the rojection 'will' not be fhave found that this disturbing factor of different depth or focal lane may be minimized by somewhat reucing, in manner well understood in the art, the period of projection of one picture of a pair, so that only a slight efiect thereof will be utilized, but which will nevertheless make sufficient impression upon the retina to give the desired stereoscopic effect. Thisexpedient, however, is not essential.

Positives will thus be obtained from which stereoscopic projection may be had by running the film or other strip of positive thru a suitable projector, although it will be appreciated that if the negatives 10 and 11 the extent of the lateral -351' :Itwill be understood, also, that a master are made with the standard width of film the-effective width of picture of the positive will be somewhat less owingto the masking or displacement of the individual pictures,

as hereinbefore set forth. This may be overcome by 'renderin opaque themasked ortions of the positive, whether at the le or right side of the particular picture, leaving the eye to retain the impression created by the previously shown picture over the dark space which will be projected by the masked opaque portion of the ensuin picture. For example, reference being ha more particularly to 7 and 8, 1t will be noted that the consecutive pictures 1 R, 1 L, are laterally displaced with reference to each other and that the strip 20 of the one series, of

pictures is matched by .a corresponding blank space 21 of the other series. I have found that by rendering opaque the portion 21 of the film as in exposln same to light, that the image or portion 0 the picture 20 will persist in the retina during the interval required for the portion 21 to be shown; and that therefore the continuity of the said lateral portion 20 will not be impaired by the intenaning darkened manner, the width of t e picture is not reduced, in fact the same ma be increased to isplacement.

positive once-liaving been obtained any numortion 21. In this ber of films may be derived therefrom by making a master negative in the usual manner and from which in turn the desired positives forgeneral distribution may be printed.

I claim: a

1. A picture film or strip having a series.

of complete pictures arranged longitudinally thereof in pairs of similar pictures representing simultaneous aspects of a relatively moving object from different viewpoints, the two pictures of a pair being aligned longitudinally so that corresponding points in a predetermined focal plane of each pair will coincide in the superpositioning of a pair during projection.

2. A picture film or strip having a series of complete pictures arranged longitudinally thereof in pairs of similar pictures representing simultaneous aspects of a relatively moving object from different viewpoints, the two pictures of a pair being displaced laterally to longitudinally align the two pictures of each pair so that corresponding points in a predetermined focal plane of each pair will coincide in the superpositioning of a pair during projection.

3. A plcture film or strip having a series of complete pictures arranged longitudinally thereof in pairs of similaihpictures and taken ly thereof in pairs of similar pictures and taken simultaneously from different points,

the two pictures of a -pair being aligned longitudinally so that corresponding points in a given; focal plane of each pair will coincide in the superpositioning of a pair during projection and the alternate, opposite overhanging side portions being opaque.

5. In the stereoscopic projection of pietures: photographing, in continuous succession and inpairs as complete pictures and simultaneously, the subject from two sep-' 'arated points upon sensitized surfaces and preparing negatives therefrom, providing a positive from said. negatives by arrangm thereon the pairs longitudinally thereof, an by displacing the respective pictures of a pair laterally of said positive to cause the respective points of a predetermined focal plane of each pair to coincide when superposed in projection.

6. In the stereoscopic projection of picture's: photographing, in continuous succes sion and in airs as complete pictures and simultaneous y, the subject from two separated pointsupon sensitized surfacesand preparing negatives therefrom, providing a positive from said negatives by arranging.

thereon the pairs longitudinally thereof and by displacing the respective pictures of apair laterally of said positive to cause the respective points of a predetermined focal plane of each pair to coincide when superposed in projection, and projecting same upon a screen.

7. In the stereoscopic projection of picmined focal plane of each pair to' coincide when superposed in projection, and projecting same upon a screen, the period of projection of one picture of a pair being less than that of the other.

8. In the stereoscopic projection of pietures: photographing, in pairs as complete pictures and simultaneously, the subject from two separated points upon sensitized surfaces and preparing negatives therefrom, providing a positive from said ne atives by arranging the pairs thereon longitudinally thereof, and by displacing the respective pictures of a pair laterally of said positive to cause the respective points of a predetermined focal plane of each pair to coincide when superposed in projection, rendering opaquealternate and opposite overhanging side portions, and projecting the positive upon a screen.

9. In the stereoscopic projection of pietures: photographing, in pairs as complete pictures and simultaneously, the subject from two separated points upon sensitized surfaces and preparing negatives therefrom, providing a positive from said negatives by arranging thereon the pairs longitudinally thereof, and by displacing the respective pictures of a pair laterally of said' positive to cause the respective points of a predetermined focal plane of each pair to coincide when superposed in projection, rendering opaque alternate and opposite overhanging side portions, and projecting the positive upon a screen, the period of projection of one picture of a pair being less than that of the other.

Signed at New York, in the county of New York and State of New York, this 7th day of May, A. D. 1920.

CHARLES P. MULLER. 

